如何从numpy 2d数组中提取子数组？ [重复]

This question already has an answer here:

这个问题在这里已有答案：

slicing arrays in numpy/scipy 3 answers
在numpy / scipy 3答案中切片数组

I'd like to extract a numpy array with a specified size from a numpy 2d array--essentially I want to crop the array. For example, if have a numpy array like this:

我想从一个numpy 2d数组中提取一个具有指定大小的numpy数组 - 基本上我想裁剪数组。例如，如果有一个像这样的numpy数组：

([1,2,3],
 [4,5,6],
 [7,8,9])

I'd like to extract a 2x2 from it and the result should be:

我想从中提取2x2，结果应该是：

([1,2],
 [4,5])

How can I do that?

我怎样才能做到这一点？

1 个解决方案

#1

Given this array:

给定这个数组：

>>> a
array([[1, 2, 3],
       [4, 5, 6],
       [7, 8, 9]])

You can slice it along both dimensions:

您可以沿两个维度切片：

>>> a[:2,:2]
array([[1, 2],
       [4, 5]])

#1